In late morning the huge birds take flight. One after another they lumber into the air like pelicans, and like pelicans they spiral upward, forming long lines as they soar across the water. As a flock they fly westward over the ocean through the middle of the day, headed for the next large land. At night they return, following trackless courses through the blind dark, sensing one another’s presence even though they cannot hear or smell.
Like chimney swifts they are drawn back to their nests amid the cities, warehouses, and factories. Like starlings they whirl in an endless murmuration as they move toward their roosts in the golden light of dawn. But they will not rest long. Soon they will take to the skies again in their ceaseless quest.
In winter, many among their number migrate like shorebirds. They scuttle to and fro between the mainland and warm islands, seeking subsistence among the tropical beaches and palm trees. Sometimes they travel like schooling fish along the edge of a coral reef, the groups passing one another in continuous gyre, ever-changing and yet with never a collision between opposing members.
Elsewhere they move like foraging sparrows, taking off and setting down in seemingly chaotic motion. Voracious and noisy, their clamour fills the air as they gather sustenance, transporting it to their homes among the towers of New York and Shanghai. They become busier and more numerous, flying farther and more frequently as they compete for resources.
Far from this cacaphony, the largest birds are in their true element somewhere out in the blue, out over the open sea. Like the albatross they can soar for hours with never a flap of their huge wings. Unlike the albatross, though, they are a rare sight around the great southern ocean where food is scarce. Instead, they follow their traditional migration paths, chasing the rich schools of tourists and traders between LAX and PAR, SAO and SEL.
Although these birds seem so successful today, as a paleontologist taking the long view I have to wonder about their continued survival. Their success may be their own greatest enemy. Like goats living on an oceanic island or jellyfish dying in a tropical lagoon, their numbers may actually be changing the environment in which they exist. In the not too distant future, environmental impacts may force their behaviour to change. Will they still be as abundant fifty years from now?
This week, I started looking at these pages that show where all scheduled flights in the world are located. I was shocked by the sheer numbers along the main flyways, and intrigued at how much they look like flocks of birds or schools of fish. I wonder: has anyone ever applied the modelling of swarming organisms to the flight organization of aircraft?
© Graham Young, 2013